30
Idea: weaken arrow contracts Intuition: only if you are interested in an application can you use information about it Open: how do finite models get affected? Open: how does completeness get affected? Tension!

31
Is completeness really lost? * HANDWAVE ARG WARNING

32
… and does it matter? All timeouts for SAT problems  ~ a second each Also helps prove things faster! (except for Z3 magic )

33
It’s really verification vs. model checking We are aiming to use the same hammer on two maybe very different problems …. We design a logic for proving specifications … which is also good in finding counterexamples! Is it reasonable to try and reconcile both? Should we be looking at each separately?

38
Question: what about completeness? For those f(t) that would be called we have all “knowledge”. For those f(t) that /are not called/ the unmodified theory must have been able to prove the goal assuming they were just unr. Oh, what about functions that were both defined and given a contract? Then we are in trouble, when they yield information about some other variable in the closure …